📩 09/04/2023 18:18
What is High Speed Train: Exactly 63 years ago, in 961, I was a student at the boarding Railway Vocational High School in Ankara. The Vocational Railroad magazine has illustrated news about high-speed trains in Japan:
” The distance between Tokyo and Osaka is 500 km. The high-speed trains used to cover this distance in two hours without stopping. ” Such a high-speed train technology could not even be imagined in our country. At that time, steam trains were running on our railways throughout our country, even between important centers. The highest speed they can do is 90 km per hour. was. There were motor trains, trains working with diesel locomotives were still at the stage of meeting the technology of our country. Steam trains continued to exist in our country until the mid-1980s. After this stage, trains pulled by diesel locomotives and trains pulled by electric locomotives between important centers such as Ankara - Istanbul continued to dominate as the most advanced technology for our country. The average speed of even express trains from passenger trains is 50 km per hour. until the beginning of the 2000s.
In the railway literature, trains are divided into three groups:
- Passenger trains
- Cargo trains
- Business trains
The last 8-10 is divided into three categories in terms of speed in the modern railway literature.
- REGIONAL TRAIN for trains up to 160 km / h.
- Its speed per hour is 160 - 250 km. FAST TRAIN to trains
- The speed on the hour is 250 km. and more trains are called HIGH SPEED TRAIN [YHT].
The technical specifications that I will describe hereafter relate to the standards of High Speed Train technology.
The political power that changed in the first years of the new millennium recalled the importance of Railway transportation, which it neglected and pushed aside in the country's economy for 50 - 60 years. Thus, he quickly initiated the work of renovating neglected maintenance and very worn parts of conventional lines, besides, he pressed the button to bring the high-speed train technology to our country. As it is known, construction started between Ankara and Eskişehir, that is, in the most suitable environment of our country as land condition. It was commissioned in 5, 2007 years later. Then the Ankara - Konya line was built and put into service. As it is known now, Eskişehir - Istanbul High Speed Train Construction, which has been under construction for 5 years, has been completed. Test drives continue. It will be put into service soon.
Our people loved High Speed Train technology, which is a great competitor and alternative to airline transportation.
As expected, High Speed technology is a very advanced technology. The road infrastructure and superstructure is a different technology with the high standards of the towed and towed vehicles that will travel on this road. The slightest negligence in the maintenance and control of the road and vehicles can cause major and irreparable accidents and losses due to high speed. However, the possibility of negligence and error as a result of daily and strict control, maintenance and intervention in the system can be prevented to a large extent. Care must be taken in the selection of personnel. A safe working environment can be provided with very good training and supervision. Thank God, there has been no major mistake or accident in the business so far. The system is settled. In addition, it brought the western-style systematic and meticulous working environment to our country and made it a tradition.
As is known, as in every construction, there is infrastructure and superstructure in the railway. Infrastructure includes constructions such as splitting [crossing elevations] filling [crossing pits] bridge [overcoming water barriers] viaduct [overcoming large and long pits] tunnel [overcoming mountains and hills] underpass and overpass bridges, which form the platform on which the superstructure is laid. It must be of a quality standard to carry the dynamic load of dynamic high-speed vehicles that will pass over these constructions. This is very costly compared to infrastructure construction on conventional lines. Its standards are determined by international agreements.
The superstructure is formed by laying concrete traverses manufactured in a special standard on the “ballast”, which consists of pieces of broken stones of certain quality and standards laid on the platform, and by connecting a pair of rails made of certain standards and quality on these traverses. High Speed Train rails are in wider cross-section and weight compared to conventional lines.
In addition, High Speed Train series (sets) are also included in the superstructure. As you can imagine, these must be of standard and quality, such as a particularly powerful engine and vehicle axles not burning at high speed.
"Superstructure geometry" is also very important in YHT road technology. Let's briefly describe the relevant basic terms to understand this topic:
When we consider the road in the vertical direction; If there is no elevation [height] difference between two specific points of the road, such a road is called a straight road, and if there is a height difference between two points, it is called an inclined or sloping road. In the YHT standard, the road should be at zero slope or very close to zero slope, with very little slope. Because sloped roads, namely ramps, are speed-limiting formations.
When we consider it in the horizontal direction, there are two different types of roads, such as the straight road and the curved road. The radius of curved paths is the arc of a given circle. And curved roads are called curves in road technology. The larger the radius of the curves, the faster the vehicles on it can travel. Limits the speed as the radius gets smaller. For example, if the curve radius is 300 meters on a conventional line, the maximum speed of the vehicles is 70 km/h. When this speed is exceeded, vehicles can be thrown out of the center of the curve and overturned. Because, according to the physics rule, circularly rotating objects are pushed out of the center of the circle by the effect of centrifugal force and as a result they are thrown away. For this reason, curves in the YHT standard should not be at all or at least in very large radii such as 3500 - 5000 meters, close to the "right path".
These superstructure geometry standards, ie zero and zero inclined roads, very large radius curves, also affect the infrastructure standards and YHT road construction of large, high, long and wide bridges, tunnels, viaducts have to be built. As a result, the cost of road construction is very high. It is very difficult to realize these standards in very rough terrain.